The invention relates to an ink-jet image recording method, particularly relates to an ink-jet image recording method in which no crack is occurred on the surface of the image, the surface has a high glossiness and the ink is rapidly absorbed.
Recently, the technology of ink-jet is considerably progressed and the printed image is attained to the level of usual photographs by the combination of the technology of printer, ink and the exclusive recording medium. Accompany with the improvement of the image quality, the durability of the ink-jet image becomes to be compare with that of the silver halide photograph. Therefore, the following problems have been pointed out; the weakness of water resistively and anti-spreading ability caused by transfer of the colorant and the degradation of the colorant caused by the low resistivity against to light and to the oxidant gas.
Many methods have been proposed for improving the durability of the dye ink image. Regarding the improvement of the ink-jet recording medium, hereinafter simply referred to as the recording medium, Japanese Patent Examined Publication No. 2-31673 discloses a method in which an image is recorded on a medium having a layer composed of a particle of thermoplastic organic polymer provided on the outermost surface of the recording medium, and then the thermoplastic polymer particle is fused to form a continuous layer functioning as a protective layer. Thus improvements on the water fastness and the weather resistance, and the glossiness providing to the image can be attained.
However, the usual recording medium having the layer composed of the thermoplastic organic polymer particle on the outermost surface thereof causes the following problems. First, the glossiness of such the recording medium is insufficient compared with that of the silver salt photograph even though the glossiness is given by the fixing treatment. Such the problem is made remarkable when a pigment ink is used. An image defect or degradation of image quality is particularly occurred when the thermal fixing is applied just after the printing for the purpose of rapid image formation. Secondly, image quality degradation is occurred caused by formation of the bleeding or beading of the color since the ink absorbing speed was reduced by the presence of the layer composed of the thermoplastic resin particles. Particularly, the degradation of the image quality has been become a large problem since the speed of the printer has be made higher for corresponding to the requirement of high-speed printing. Thirdly, the thermoplastic resin added for forming the glossiness causes formation of cracks at the surface of the recording medium. When the glass transition temperature of the thermoplastic resin is low, the resin is fused at the temperature of in the course of the coating and drying process so that the resin functions as the binder. However, when the heating treatment is applied after the printing, a resin having a high transition point is to be selected so that the resin is not fused by the temperature at the production process or that at the storage after the production of the recording medium. In such the recording medium, the amount of the binder is substantially reduced. It is supposed that the strength of the coated layer is lowered so as to be occurred the cracks. The formation of the cracks can be inhibited by reducing the amount of the thermoplastic resin but the lowering of the glossiness is occurred.
Japanese Patent Publication Open to Public Inspection, hereinafter referred to as JP O.P.I. No. 7-117334 discloses technology relating to the ink-jet recording sheet comprising polyvinyl alcohol or PVA having a degree of polymerization of 4,000 or more and inorganic fine particles having an average particle diameter of less than 0.1 xcexcm. The glossiness is surely improved by such the technique. However, considerable viscosity raising of the coating liquid for producing the ink-jet recording sheet is occurred by such the measure so that troubles on the coating tend to be occurred.
JP O.P.I. No. 8-318671 discloses technology in which a layer comprising hydrophobic particles having an average particle diameter of not more than 0.3 xcexcm dispersed in a medium of a water absorbable binder is piles. The object of the technology is the improvement of optical transparency of the transparent recording medium using a transparent substrate.
JP O.P.I. No. 2000-211243 discloses technology relating to an ink-jet coating material comprising a binder and an aqueous dispersion containing a particle having a specified specific surface area and particle diameter. The object of this technology is to improve the water resistance and transparency of the image formed by a dye ink.
The invention relates to an ink-jet image recording method improved in the occurrence of the cracks on the image surface during the storage extend over a long duration.
As a result of the investigation by the inventors, the following problems are found.
First, the glossiness is insufficient compared with that of the silver salt photograph.
Secondly, an old or commercially used high speed printer has a low ink absorbing speed, and the image quality is considerably degraded by occurrence of beading and color bleeding.
Thirdly, it is difficult to stably produce a satisfactory product with a lower cost since crack default occurs in the coating and drying process.
Fourthly, the cracks are often occurred on the surface of the image when the image is stored for a long period.
The invention is carried out on the above-mentioned background. The object of the invention is to provide an ink-jet image recording method by which the crack occurrence on the image surface is inhibited and an excellent ink absorbing speed is obtained.
The invention and the embodiment thereof are described below.
An ink-jet image recording method comprising the steps of
forming an image on an ink-jet recording medium having at least one ink absorption layer on resin coated paper (RC paper), in which the outermost layer comprises an aqueous emulsion of thermoplastic resin particles which is synthesized in the presence of polyvinyl alcohol as a protective colloid for emulsion polymerization, and then treating the recording medium by heat.
The degree of saponification of the polyvinyl alcohol is preferably not more than 90%.
The glass transition temperature of the thermoplastic resin particles is preferably from 40 to 100xc2x0 C.
The average particle diameter of the thermoplastic resin particles is preferably not more than 300 nm.
The amount of the solid composition of the thermoplastic resin particles is preferably from 1 to 10 g/m2.
In one of the embodiments, the degree of polymerization of the polyvinyl alcohol is preferably from 300 to 1,500.
The image is preferably formed by a pigment ink.
The outermost layer preferably further contains inorganic fine particles.
An ink-jet image recording method comprising the steps of forming an image on an ink-jet recording medium having an ink absorption layer on RC paper, in which the outermost layer comprises an aqueous emulsion of thermoplastic resin particles which is synthesized in the presence of polyvinyl alcohol having a degree of polymerization of from 1,500 to 4,500 as a protective colloid for emulsion polymerization, drying the ink-jet recording medium having the image formed, and then treating the recording medium by heat.
An ink-jet image recording method comprising the steps of forming an image on an ink-jet recording medium having an ink absorption layer on RC paper, in which the outermost layer comprises an aqueous emulsion of thermoplastic resin particles which is synthesized in the presence of polyvinyl alcohol having a degree of polymerization of from 1,500 to 4,500 as a protective colloid for emulsion polymerization, and then treating the recording medium by heat and pressure with a pressure of from 5 to 20 MPa.